The invention relates to a muscle training apparatus allowing its user to exercise his body, especially his lower limbs for training or sporting purposes. For example, the apparatus is useful for initial instruction, perfecting and training in sliding sports such as snow or water skiing.
Different apparatus of this type are well known today. Depending on its design, such an apparatus more or less faithfully simulates movements usually made during the practice of such a sport.
One of the known apparatus (U.S. Pat. No. 2 455 274 issued to Scriver on Nov. 30, 1948) comprises a plate in the form of a circular sector resting on a substantially horizontal reference surface. A tip of the arc of this sector rests on the surface. The sector is also attached to the surface through a foot member having a hinge at its top substantially at the level of the origin of the radius of curvature of the plate.
To perform a combination of movements on Scriver's apparatus, the user's feet are only connected to the plate by means of shoes guided in translation on the top of the plate whereby they are disposed between two concentric curved reels, the reels having a curvature opposite that of the arc of the plate.
Taking into account the small degrees of freedom left to the parts of Scriver's device, it is apparent that the user can only carry out certain movements.
In addition, it should be noted that the conditions in which they are carried out are very often different than those to which the user is subjected during the real performance of his sport. When the user places his lower limbs outwardly of his fictitious path, either to one or other of the sides of a plate, the weight of the user causes the plate to slant inversely to the real slant of the ground. (The real slant of the ground is the slant which would normally be encountered when actually skiing.)
Furthermore, because of the particular guiding of the above mentioned parts, the above mentioned parts and the feet of the user cannot slant with respect to the plate.
It is apparent that this movement called "taking the edge" is of prime importance in the practice of a sliding sport such as skiing.
Consequently, although allowing a certain number of movements, this type of apparatus cannot prepare for the practice of a sport such as snow or water skiing since the sensations felt on the apparatus are quite different from those actually experienced in carrying out the sport.
An apparatus (U.S Pat. No. 4,074,903 issued Feb. 21, 1978 to de Aux) also has a slanted plated, on which shoes are directly associated by means of a ball joint. On the shoes there is provided a sole which may move parallel to the plane of the shoe in all directions but slightly and insufficient for simulating the practice of skiing. Moreover, the feet generally remain in the same position and the movements are created by actuating cylinders varying the slant of the plate.
Another known apparatus (French Pat. No. 1 595 452 to Paulus dated July 17, 1970) includes a plate which is fixed with respect to the reference surface and which has an arcuate upper surface forming a track on which two carriages move in translation.
However, instead of these carriages being, as in the first mentioned patent, guided and held between two curved rails, they rest simply on rails provided on the top of the base. The carriages are guided by two rods which, at one of their ends, are hinged substantially to the origin of the radius of curvature of the track whereas, at their other ends, they are fixed respectively to the shoes. (The origin is the center of a circle realized by extending the arc of the arcuate track upper surface into a complete circle).
Furthermore, in order to allow movement such as "taking the edge", a shoe is associated with each carriage by means guiding the shoe in translation along an axis parallel to the rod of the particular carriage and also in rotation about this same axis.
At a certain slant of the shoe, the rotation allows the carriage to be blocked in translation on the plate by the friction of a lining fixed to the shoe on at least one wheel of the carriage.
Since the origin of the radius of curvature of the track is in front or behind the track but in the plane of this track, the track is flat and substantially horizontal.
Therefore the track does not allow the user to adopt a position in which the carriage is slanted forwardly or rearwardly or to the side.
Because of the small number of degrees of freedom which such an apparatus of the Paulus design offers a user, the Paulus type of apparatus gives good results for certain movements, but the movements are nevertheless limited.
The Paulus design does not allow the skier to assume a position leaning to a greater or lesser extent upstream or downstream or an orientation of the ski different from the of the rods to be represented.
In addition, "taking the edge" by blocking at least one wheel of a shoe does not accurately simulate the actual skiing movement.
Moreover, the design of the shoe (which allows it to cause braking of at least one of the wheels of the carriage) is such that the shoe must be suitably adjusted incrementally to avoid tipping the carriage.
Finally, known apparatus do not allow one to adjust the degree of difficulty of the skiing operation depending on the experience of the user.